syslim/t_sysconf.c

This is syslim/t_sysconf.c (Listing 11-1, page 216), an example from the book, The Linux Programming Interface.

The source code file is copyright 2022, Michael Kerrisk, and is licensed under the GNU General Public License, version 3.

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In the listing below, the names of Linux system calls and C library functions are hyperlinked to manual pages from the Linux man-pages project, and the names of functions implemented in the book are hyperlinked to the implementations of those functions.

 

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  Cover of The Linux Programming Interface

Function list (Bold in this list means a function is not static)

/* t_sysconf.c

   Demonstrate the use of sysconf() to retrieve system limits.
*/
#include "tlpi_hdr.h"
static void             /* Print 'msg' plus sysconf() value for 'name' */
sysconfPrint(const char *msg, int name)
{
    long lim;

    errno = 0;
    lim = sysconf(name);
    if (lim != -1) {        /* Call succeeded, limit determinate */
        printf("%s %ld\n", msg, lim);
    } else {
        if (errno == 0)     /* Call succeeded, limit indeterminate */
            printf("%s (indeterminate)\n", msg);
        else                /* Call failed */
            errExit("sysconf %s", msg);
    }
}
int
main(int argc, char *argv[])
{
    sysconfPrint("_SC_ARG_MAX:        ", _SC_ARG_MAX);
    sysconfPrint("_SC_LOGIN_NAME_MAX: ", _SC_LOGIN_NAME_MAX);
    sysconfPrint("_SC_OPEN_MAX:       ", _SC_OPEN_MAX);
    sysconfPrint("_SC_NGROUPS_MAX:    ", _SC_NGROUPS_MAX);
    sysconfPrint("_SC_PAGESIZE:       ", _SC_PAGESIZE);
    sysconfPrint("_SC_RTSIG_MAX:      ", _SC_RTSIG_MAX);
    exit(EXIT_SUCCESS);
}

 

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