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   perror.3p    ( 3 )

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Пролог (Prolog)

This manual page is part of the POSIX Programmer's Manual.  The
       Linux implementation of this interface may differ (consult the
       corresponding Linux manual page for details of Linux behavior),
       or the interface may not be implemented on Linux.

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Имя (Name)

perror — write error messages to standard error

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Синопсис (Synopsis)

#include <stdio.h>

       void perror(const char *s);

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Описание (Description)

The functionality described on this reference page is aligned
       with the ISO C standard. Any conflict between the requirements
       described here and the ISO C standard is unintentional. This
       volume of POSIX.1‐2017 defers to the ISO C standard.

       The perror() function shall map the error number accessed through
       the symbol errno to a language-dependent error message, which
       shall be written to the standard error stream as follows:

        *  First (if s is not a null pointer and the character pointed
           to by s is not the null byte), the string pointed to by s
           followed by a <colon> and a <space>.

        *  Then an error message string followed by a <newline>.

       The contents of the error message strings shall be the same as
       those returned by strerror() with argument errno.

       The perror() function shall mark for update the last data
       modification and last file status change timestamps of the file
       associated with the standard error stream at some time between
       its successful completion and exit(), abort(), or the completion
       of fflush() or fclose() on stderr.

       The perror() function shall not change the orientation of the
       standard error stream.

       On error, perror() shall set the error indicator for the stream
       to which stderr points, and shall set errno to indicate the
       error.

       Since no value is returned, an application wishing to check for
       error situations should call clearerr(stderr) before calling
       perror(), then if ferror(stderr) returns non-zero, the value of
       errno indicates which error occurred.

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Возвращаемое значение (Return value)

The perror() function shall not return a value.

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Ошибки (Error)

Refer to fputc(3p).

       The following sections are informative.

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Примеры (Examples)

Printing an Error Message for a Function
       The following example replaces bufptr with a buffer that is the
       necessary size. If an error occurs, the perror() function prints
       a message and the program exits.

           #include <stdio.h>
           #include <stdlib.h>
           ...
           char *bufptr;
           size_t szbuf;
           ...
           if ((bufptr = malloc(szbuf)) == NULL) {
               perror("malloc"); exit(2);
           }
           ...

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Использование в приложениях (Application usage)

Application writers may prefer to use alternative interfaces
       instead of perror(), such as strerror_r() in combination with
       fprintf().

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Обоснование (Rationale)

None.

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Будущие направления (Future directions)

None.

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Смотри также (See also)

fprintf(3p), fputc(3p), psiginfo(3p), strerror(3p)

       The Base Definitions volume of POSIX.1‐2017, stdio.h(0p)

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