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Diffstat (limited to 'man3p/errno.3p')
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diff --git a/man3p/errno.3p b/man3p/errno.3p new file mode 100644 index 000000000..951a1428b --- /dev/null +++ b/man3p/errno.3p @@ -0,0 +1,74 @@ +.\" Copyright (c) 2001-2003 The Open Group, All Rights Reserved +.TH "ERRNO" P 2003 "IEEE/The Open Group" "POSIX Programmer's Manual" +.\" errno +.SH NAME +errno \- error return value +.SH SYNOPSIS +.LP +\fB#include <errno.h>\fP +.SH DESCRIPTION +.LP +The lvalue \fIerrno\fP is used by many functions to return error values. +.LP +Many functions provide an error number in \fIerrno\fP, which has type +\fBint\fP and is defined in \fI<errno.h>\fP. The value of \fIerrno\fP +shall be defined only after a call to a function +for which it is explicitly stated to be set and until it is changed +by the next function call or if the application assigns it a +value. The value of \fIerrno\fP should only be examined when it is +indicated to be valid by a function's return value. +Applications shall obtain the definition of \fIerrno\fP by the inclusion +of \fI<errno.h>\fP. No function in this volume of IEEE\ Std\ 1003.1-2001 +shall set +\fIerrno\fP to 0. +.LP +It is unspecified whether \fIerrno\fP is a macro or an identifier +declared with external linkage. If a macro definition is +suppressed in order to access an actual object, or a program defines +an identifier with the name \fIerrno\fP, the behavior is +undefined. +.LP +The symbolic values stored in \fIerrno\fP are documented in the ERRORS +sections on all relevant pages. +.SH RETURN VALUE +.LP +None. +.SH ERRORS +.LP +None. +.LP +\fIThe following sections are informative.\fP +.SH EXAMPLES +.LP +None. +.SH APPLICATION USAGE +.LP +Previously both POSIX and X/Open documents were more restrictive than +the ISO\ C standard in that they required \fIerrno\fP +to be defined as an external variable, whereas the ISO\ C standard +required only that \fIerrno\fP be defined as a modifiable +lvalue with type \fBint\fP. +.LP +An application that needs to examine the value of \fIerrno\fP to determine +the error should set it to 0 before a function call, +then inspect it before a subsequent function call. +.SH RATIONALE +.LP +None. +.SH FUTURE DIRECTIONS +.LP +None. +.SH SEE ALSO +.LP +\fIError Numbers\fP , the Base Definitions volume of IEEE\ Std\ 1003.1-2001, +\fI<errno.h>\fP +.SH COPYRIGHT +Portions of this text are reprinted and reproduced in electronic form +from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology +-- Portable Operating System Interface (POSIX), The Open Group Base +Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of +Electrical and Electronics Engineers, Inc and The Open Group. In the +event of any discrepancy between this version and the original IEEE and +The Open Group Standard, the original IEEE and The Open Group Standard +is the referee document. The original Standard can be obtained online at +http://www.opengroup.org/unix/online.html . |