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Text File | 1993-03-07 | 17.4 KB | 573 lines

This is simply an enhancement to Acorn's DDE C help file to make it more user friendly. It annoyed me just slightly that most of the help I needed was in the file, but that you needed to type the EXACT word to find it. No use since I can never remember these things, and there were no Indexes. All this has now been solved. Delete the text up to and including the "DELETE UP TO HERE" marker and then add it on to the file called "DDE.!SrcEdit.help.C" Hope you find this useful. To contact me ask for help on topics. DELETE UP TO HERE %version This is help file version 1.02 Improvements : Version 1.00 Original Acorn help file Version 1.01 Added help on the libraries Version 1.02 Added help on C commands as well as an index %help Try help on 'topics', 'commands', 'libraries' , 'general' or 'index'. %topics Help topics available are : commands - a list of C commands libraries - name of libraries available general - lists of further help topics grouped by general area index - an index of all help topics available This extension to the help file was provided by Justin Williams (28/06/92) To contact me write to : PO Box 1051 Wandsbeck 3631 South Africa E-Mail : williamj@shrike.und.ac.za Future updates will be made available. %statements See commands %keywords See commands %commands The list of C commands follows : block break case continue do else for goto if label null return switch while For futher help ask for help on a particular command. %block Block statements are defined using the curly brackets {} Eg. { printf("Hello"); printf("Goodbye"); } would be treated as one statement %break The statement break; causes termination of the smallest enclosing while, do, for or switch statement. Control passes to the statement following the terminated statement. %continue The statement continue; passes control to the loop-continuation portion of the smallest enclosing while, do, or for statement i.e. to the end of the loop. Eg. while (...) { do { for (....) { ... ... ... contin: ; contin: ; contin: ; } } while (...); } In each case, a continue statement would be the equivalent of a goto contin statement. %case See 'switch'. %do This statement has the form : do statement while (expression) The substatement is executed repeatedly until the value of the expression becomes zero. The test takes place after the execution of the statement. %else See 'if'. %goto Control may be transferred unconditionally by means of the statement goto identifier; The identifier must be a label located in the current function. %if The two forms of the conditional statement are : if (expression) statement if (expression) statement else statement The expression is evaluated and if it is non-zero, the first sub- statement is executed. The else is executed if it is zero. If there is an ambigouous else statement, it is connected with the last else-less statement. %label Any statement may be preceded by label prefixes of the form identifier : which serves to declare the identifier as a label. The only use of a label is as the target of a goto. The scope of the label is the current function, excluding any sub-blocks in which it has been re-defined. %null The null statement has the form ; A null statement is useful to carry a label just before the } of a compound statement or to supply a null body to a loop such as while. %return A function returns to its caller by means of the return statement which has one of the following forms return ; return expression ; In the first case the returned value is undefined. In the second case the value of the expression is returned. If required, the value is converted, as if by assignment, to the type of the function in which it appears. Flowing off the end of the function is the same as returning no value. %switch The switch statement causes control to be transferred to one of several statement depending on the value of an expression. It has the form : switch (expression) statement The usual conversion is done on the expression, but the result must be of type int. The statement is typically compound. Any statement within the compound statement must be labelled with one or more case prefixes as follows : case constant-expression : where the constant expression must be int. No two cases must be the same. There may also be at most one statement prefix of the form default : When the switch statement is executed its expression is evaluated and compared with each case consant. If one of the cases matches, control is passed to the statement following the matched case prefix. If there are no matches, control is passed to the default prefix. If there is no default, none of the statements will be executed. Each case must be ended with a break statement. Example : Switch choice { case 'A' : printf("A selected"); break; case 'B' : printf("B selected"); break; default : printf("no valid selection"); break; } %while The while statement has the form while (expression) statement The substatement is executed repeatedly as long as the expression remains non-zero. The test takes place before the execution of the statement. %libraries Libraries available are : * assert.h - define assert debugging macro * ctype.h - contains info used by character classification and conversion macros such as isalpha. errno.h - defines constant mnemonics for the error codes float.h - contains parameters for floating point routines kernel.h - interface to host operating system limits.h - contains environmental parameters & info about limitations * locale.h - declares routines and data types to handle country standards * math.h - declares prototypes for maths functions * setjmp.h - declares type jmp_buf and also routines longjmp and setjmp * signal.h - declares ssignal and gsignal * stdarg.h - defines macros for reading the argument list in functions * stddef.h - defines a number of standard data types and macros * stio.h - defines types, macros and functions needed for standard I/O * stdlib.h - declares several commonly used routines * string.h - declares several string and memory manipulation routines swis.h - sets constants defining the RISC OS SWI numbers * time.h - defines some time routines and structures * varargs.h - used for variable parameter lists If you can't find the information you need in the help file, try and have a look in the header file. More information is given there. * indicates further help available on that library, leave off the .h %varargs.h See 'varargs' %varargs VarArgs - variable parameter list handling va_dcl va_start va_end va_arg Ask for help on the function for further information. %stddef.h See 'stddef' %stddef StdDef - Standard Defintions offsetof Type defintions : ptrdiff_t size_t wchar_t Ask for help on the function or type for further information. %stdarg.h See 'stdarg' %stdarg StdArg - Standard Arguments va_start va_arg va_end Ask for help on the function for further information. %signal.h Signal - Functions for handling conditions that may be encountered during execution of a program signal raise Associated variables : SIG_DFL SIG_ERR SIG_IGN SIGABRT SIGFPE SIGILL SIGINT SIGSEGV SIGTERM SIGSTAK SIGUSR1 SIGUSR2 SIGOSERROR Ask for help on the function or variable for further information. %setjmp.h SetJmp - Functions for dealing with abnormal calling of low level routines setjmp longjmp Ask for help on the function for further information. %locale.h See 'locale' %locale Locale - Handles national characteristics setlocale localeconv Ask for help on the function for further information. %asset.h See 'assert' %stdio.h See 'stdio' %stdio StdIO - Standard IO routines clearerr fclose feof ferror fflush fgetc fgetpos fgets fopen fprintf fputc fputs fread freopen fscanf fseek fsetpos ftell fwrite getc getchar gets perror printf putc putchar remove rename rewind scanf setbuf setvbuf sprintf sscanf tmpfile tmpnam ungetc vfprintf vprintf vsprintf Ask for help on the function for further information. %time.h See 'time' %time Time - Time manipulating functions clock difftime mktime time asctime ctime gmtime localtime strftime Ask for help on the function for further information. %stdlib.h See 'stdlib' %stdlib Stdlib - Standard library functions abort abs atexit atof atoi atol bsearch calloc div exit free getenv labs ldiv malloc mblen mbstowcs mbtowc qsort rand realloc srand strtod strtol strtoul system wcstombs wctomb _ANSI_rand _ANSI_srand Ask for help on the function for further information. %math.h See 'math' %math Math - Maths functions atof ceil exp fabs floor fmod frexp ldexp log log10 modf pow sqrt Ask for help on the function for further information. See 'trig' for the trig functions defined in Math.h %ctype.h See 'ctype' %ctype Ctype - Classification and conversion routines Classification routines : isalnum - returns true if arg is alphabetic or numeric isalpha - returns true if arg is alphabetic iscntrl - returns true if arg is a control character isdigit - returns true if arg is a decimal digit isgraph - returns true if arg is a printable character other than space islower - returns true if arg is a lower-case letter isprint - returns true if arg is a printable character ispunct - returns true if arg is a printable but not space or alpha-numeric isspace - returns true if arg is a white-space character isupper - returns true if arg is an upper-case letter isxdigit - returns true if arg is a hex digit (0-F) Conversion routines : tolower - returns the lower-case equivalent of arg toupper - returns the upper-case equivalent of arg %general Further help is available on : memory operators string trig %operators Unary and Binary operators * multiplication / division % modulus + addition - subtraction Increment and Decrement operators ++ increment Usage : ++b increments b before using it -- decrement b++ increments b after using it Bitwise operators << shift left | or >> shift right ^ exclusive or & and ~ not Relational operators > greater than >= greater than or equal to < less than <= less than or equal to == equal to != not equal to Logical operators && and || or ! not %trig Trig - Trigonometric functions Defined in : math.h acos asin atan atan2 cos cosh sin sinh tan tanh %string String - String functions Defined in : string.h strcat - adds copy of source to end of destination strchr - scans a string for the 1st occurence of a given string strcmp - compares one string to another strcpy - copies one string into another strcspn - scans a string for the 1st segment not containing any subset of a given set if characters strlen - calculates the length of a string strncat - adds n (or less) characters from source to end of destination strncmp - compares a portion of one string to a portion of another strncpy - copies a number of bytes from one string into another, truncating or padding as necessary strpbrk - scans a string for the 1st occurrence of any character from a given set strspn - scans a string for the 1st segment that is a subset of a given set of characters strstr - scans a string for the occurence of a given sub-string strtod - converts a string to a double value strtok - searches one string for tokens, which are separated by delimiters which are defined in another strtol - converts a string into a long value Related : See 'memory' for other functions defined in string.h %memory Memory - memory related functions Defined in : String.h memcpy - copies a block of n bytes from source to destination memmove - as above, but works for overlapping memory areas memset - sets all the bytes of an area to a specific character memcmp - compares two strings, for a length of exactly n characters memchr - searches the first n bytes of array s for character ch Related : See 'string' for other functions defined in string.h %string.h See 'string' for string functions See 'memory' for memory functions %Index Try 'index' %INDEX Try 'index' %index C Index : Help is available on the following topics : (Note : Case is essential) abort abs acos asctime asin assert asset.h atan atan2 atexit atof atoi atol block break bsearch BUFSIZ calloc case ceil CHAR_BIT CHAR_MAX CHAR_MIN clearerr clock CLOCKS_PER_SEC clock_t commands continue cos cosh ctime ctype ctype.h DBL_DIG DBL_EPSILON DBL_MANT_DIG DBL_MAX DBL_MAX_10_EXP DBL_MAX_EXP DBL_MIN DBL_MIN_10_EXP DBL_MIN_EXP difftime div div_t do EDOM else EOF ERANGE errno ESIGNUM exit EXIT_FAILURE EXIT_SUCCESS exp fabs fclose feof ferror fflush fgetc fgetpos fgets FILE FILENAME_MAX floor FLT_DIG FLT_EPSILON FLT_MANT_DIG FLT_MAX FLT_MAX_10_EXP FLT_MAX_EXP FLT_MIN FLT_MIN_10_EXP FLT_MIN_EXP FLT_RADIX FLT_ROUNDS fmod fname fopen fpos_t fprintf fputc fputs fread free freopen frexp fscanf fseek fsetpos ftell fwrite general getc getchar getenv gets gmtime goto help HUGE_VAL if index INT_MAX INT_MIN isalnum isalpha iscntrl isdigit isgraph islower isprint isprint ispunct isspace isupper isxdigit keywords label labs LC_ALL LC_COLLATE LC_CTYPE LC_MONETARY LC_NUMERIC LC_TIME LDBL_DIG LDBL_EPSILON LDBL_MANT_DIG LDBL_MAX LDBL_MAX_10_EXP LDBL_MAX_EXP LDBL_MIN LDBL_MIN_10_EXP LDBL_MIN_EXP ldexp ldiv ldiv_t libraries locale locale.h localeconv localtime log log10 longjmp LONG_MAX LONG_MIN L_tmpnam malloc math math.h mblen mbstowcs mbtowc MB_CUR_MAX MB_LEN_MAX memchr memcmp memcpy memmove memory memset mktime modf null offsetof operators perror pow printf ptrdiff_t putc putchar puts qsort raise rand RAND_MAX realloc remove rename return scanf SCHAR_MAX SCHAR_MIN setbuf setjmp setjmp.h setlocale setvbuf SHRT_MAX SHRT_MIN SIGABRT SIGFPE SIGILL SIGINT signal signal.h SIGOSERROR SIGSEGV SIGSTAK SIGTERM SIGUSR1 SIGUSR2 SIG_DFL SIG_ERR SIG_IGN sin sinh size_t sprintf sqrt srand sscanf statements stdarg stdarg.h stddef stddef.h stderr stdin stdio stdio.h stdlib stdlib.h stdout strcat strchr strcmp strcoll strcpy strcspn strerror strftime string string.h strlen strncat strncmp strncpy strpbrk strrchr strspn strstr strtod strtok strtol strtoul strxfrm switch system tan tanh time time time.h time_t tmpfile tmpnam TMP_MAX tolower topics toupper trig UCHAR_MAX UINT_MAX ULONG_MAX ungetc USHRT_MAX varargs varargs.h va_arg va_end va_start version vfprintf vprintf vsprintf wchar_t wcstombs wctomb while _ANSI_rand _ANSI_RAND_MAX _ANSI_srand The extensions to this help file were provided by Justin Williams (28/06/92)