Watcom C Library Reference : close, closedir, _control87
Watcom C Reference/A - B - C 2021. 6. 18. 17:47
Watcom C Library Reference : close, closedir, _control87
close
Synopsis : #include <io.h>
int close( int handle );
Description : The close function closes a file at the operating system level. The handle value is the file handle returned by a successful execution of one of the creat, dup, dup2, open or sopen functions.
Returns : The close function returns zero if successful. Otherwise, it returns -1 and errno is set to indicate the error.
Errors : When an error has occurred, errno contains a value indicating the type of en been detected.
| Constant | Meaning |
| EBADF | The handle argument is not a valid file handle. |
See Also : creat, dup, dup2, open, sopen
Example :
#include <fcntl.h>
#include <io.h>
void main( )
{
int handle;
handle = open( "file", O_RDONLY );
if( handle != -1 ) {
/* process file */
close( handle );
}
}
Classification : POSIX 1003.1
Systems : All
closedir
Synopsis : #include <direct.h>
int closedir( DIR *dirp );
Description : The closedir function closes the directory specified by dirp and frees the memory allocated by opendir.
Returns : The closedir function returns zero if successful, non-zero otherwise.
Errors : When an error has occurred, errno contains a value indicating the type of error that has been detected.
| Constant | Meaning |
| EBADF | The argument dirp does not refer to an open directory stream. |
See Also : _dos_find Functions, opendir, readdir
Example : To get a list of files contained in the directory \watcom\h on your default disk:
#include <stdio.h>
#include <direct.h>
void main( )
{
DIR *dirp;
struct dirent *direntp;
dirp = opendir( " \\watcom\\h" );
if( dirp != NULL ) {
for( ; ; ) {
direntp = readdir( dirp );
if( direntp == NULL ) break;
printf( "%s\n", direntp->d_name );
}
closedir( dirp );
}
}
Note the use of two adjacent backslash characters (\) within character-string constant signify a single backslash.
Classification : POSIX 1003.1
Systems : All
_control87
Synopsis : #include <float.h>
unsigned int _control87 ( unsigned int newcw, unsigned int mask );
Description : The _control87 function updates the control word of the 8087/80287/80387/80486. If mask is zero, then the control word is not updated. If mask is non-zero, then the control word is updated with bits from newcw corresponding to every bit that is on in mask.
Returns : The _control87 function returns the new control word. The description of bits defined for the control word is found in the <float.h> header file.
See Also : _clear87, _fpreset, _status87
Example :
#include <stdio.h>
#include <float.h>
char *status [2] = { "disabled", "enabled" };
void main( )
{
unsigned int fp_cw = 0;
unsigned int fp_mask = 0;
unsigned int bits;
fp_cw = _control87 ( fp_cw, fp_mask );
printf( "Interrupt Exception Masks\n" );
bits = fp_cw & MCW_EM;
printf( " Invalid Operation exception %s\n", status[ (bits & EM_INVALID) == 0 ] );
printf( " Denormalized exception %s\n", status[ (bits & EM_DENORMAL) == 0 ] );
printf( " Divide-By-Zero exception %s\n", status[ (bits & EM_ZERODIVIDE) == 0 ] );
printf( " Overflow exception %s\n", status[ (bits & EM_OVERFLOW) == 0 ] );
printf( " Underflow exception %s\n", status[ (bits & EM_UNDERFLOW) == 0 ] );
printf( " Precision exception %s\n", status[ (bits & EM_PRECISION) == 0 ] );
printf( " Infinity Control = " );
bits = fp_cw & MCW_IC;
if( bits == IC_AFFINE ) printf( "affine\n" );
if( bits == IC_PROJECTIVE ) printf( "projective\n" );
printf( "Rounding Control = " );
bits = fp_cw & MCW_RC;
if( bits == RC_NEAR ) printf( "near\n" );
if( bits == RC_DOWN ) printf( "down\n" );
if( bits == RC_UP ) printf( "up\n" );
if( bits == RC_CHOP ) printf( "chop\n" );
printf( "Precision Control = " );
bits = fp_cw & MCW_PC;
if( bits == PC_24 ) printf( "24 bits\n" );
if( bits == PC_53 ) printf( "53 bits\n" );
if( bits == PC_64 ) printf( "64 bits\n" );
}
Classification : Intel
Systems : All
This manual describes the WATCOM C library for DOS, Windows, and OS/2, It includes the Standard C Library (as defined in the ANSI C Standard).
WATCOM C Language Reference manual describes the ANSI C Programming language and extensions to it which are supported by WATCOM C/C++ (32bit)
