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If applicable, add the following below this CDDL HEADER, with the fields enclosed by brackets "[]" replaced with your own identifying information: Portions Copyright [yyyy] [name of copyright owner] .TH fgetc 3C "15 Oct 2003" "SunOS 5.11" "Standard C Library Functions" .SH NAME fgetc, getc, getc_unlocked, getchar, getchar_unlocked, getw \- get a byte from a stream .SH SYNOPSIS .LP .nf #include \fBint\fR \fBfgetc\fR(\fBFILE *\fR\fIstream\fR); .fi .LP .nf \fBint\fR \fBgetc\fR(\fBFILE *\fR\fIstream\fR); .fi .LP .nf \fBint\fR \fBgetc_unlocked\fR(\fBFILE *\fR\fIstream\fR); .fi .LP .nf \fBint\fR \fBgetchar\fR(\fBvoid\fR); .fi .LP .nf \fBint\fR \fBgetchar_unlocked\fR(\fBvoid\fR); .fi .LP .nf \fBint\fR \fBgetw\fR(\fBFILE *\fR\fIstream\fR); .fi .SH DESCRIPTION .sp .LP The \fBfgetc()\fR function obtains the next byte (if present) as an \fBunsigned char\fR converted to an \fBint\fR, from the input stream pointed to by \fIstream\fR, and advances the associated file position indicator for the stream (if defined). .sp .LP For standard-conforming (see \fBstandards\fR(5)) applications, if the end-of-file indicator for the stream is set, \fBfgetc()\fR returns \fBEOF\fR whether or not a next byte is present. .sp .LP The \fBfgetc()\fR function may mark the \fBst_atime\fR field of the file associated with \fIstream\fR for update. The \fBst_atime\fR field will be marked for update by the first successful execution of \fBfgetc()\fR, \fBfgets\fR(3C), \fBfread\fR(3C), \fBfscanf\fR(3C), \fBgetc()\fR, \fBgetchar()\fR, \fBgets\fR(3C) or \fBscanf\fR(3C) using \fIstream\fR that returns data not supplied by a prior call to \fBungetc\fR(3C) or \fBungetwc\fR(3C). .sp .LP The \fBgetc()\fR function is functionally identical to \fBfgetc()\fR, except that it is implemented as a macro. It runs faster than \fBfgetc()\fR, but it takes up more space per invocation and its name cannot be passed as an argument to a function call. .sp .LP The \fBgetchar()\fR routine is equivalent to \fBgetc(stdin)\fR. It is implemented as a macro. .sp .LP The \fBgetc_unlocked()\fR and \fBgetchar_unlocked()\fR routines are variants of \fBgetc()\fR and \fBgetchar()\fR, respectively, that do not lock the stream. It is the caller's responsibility to acquire the stream lock before calling these routines and releasing the lock afterwards; see \fBflockfile\fR(3C) and \fBstdio\fR(3C). These routines are implemented as macros. .sp .LP The \fBgetw()\fR function reads the next word from the \fIstream\fR. The size of a word is the size of an \fBint\fR and may vary from environment to environment. The \fBgetw()\fR function presumes no special alignment in the file. .sp .LP The \fBgetw()\fR function may mark the \fBst_atime\fR field of the file associated with \fIstream\fR for update. The \fBst_atime\fR field will be marked for update by the first successful execution of \fBfgetc()\fR, \fBfgets\fR(3C), \fBfread\fR(3C), \fBgetc()\fR, \fBgetchar()\fR, \fBgets\fR(3C), \fBfscanf\fR(3C) or \fBscanf\fR(3C) using \fIstream\fR that returns data not supplied by a prior call to \fBungetc\fR(3C). .SH RETURN VALUES .sp .LP Upon successful completion, \fBfgetc()\fR, \fBgetc()\fR, \fBgetc_unlocked()\fR, \fBgetchar()\fR, \fBgetchar_unlocked()\fR, and \fBgetw()\fR return the next byte from the input stream pointed to by \fIstream\fR. If the stream is at end-of-file, the end-of-file indicator for the stream is set and these functions return \fBEOF\fR. For standard-conforming (see \fBstandards\fR(5)) applications, if the end-of-file indicator for the stream is set, these functions return \fBEOF\fR whether or not the stream is at end-of-file. If a read error occurs, the error indicator for the stream is set, \fBEOF\fR is returned, and \fBerrno\fR is set to indicate the error. .SH ERRORS .sp .LP The \fBfgetc()\fR, \fBgetc()\fR, \fBgetc_unlocked()\fR, \fBgetchar()\fR, \fBgetchar_unlocked()\fR, and \fBgetw()\fR functions will fail if data needs to be read and: .sp .ne 2 .mk .na \fB\fBEAGAIN\fR\fR .ad .RS 13n .rt The \fBO_NONBLOCK\fR flag is set for the file descriptor underlying \fIstream\fR and the process would be delayed in the \fBfgetc()\fR operation. .RE .sp .ne 2 .mk .na \fB\fBEBADF\fR\fR .ad .RS 13n .rt The file descriptor underlying \fIstream\fR is not a valid file descriptor open for reading. .RE .sp .ne 2 .mk .na \fB\fBEINTR\fR\fR .ad .RS 13n .rt The read operation was terminated due to the receipt of a signal, and no data was transferred. .RE .sp .ne 2 .mk .na \fB\fBEIO\fR\fR .ad .RS 13n .rt A physical I/O error has occurred, or the process is in a background process group attempting to read from its controlling terminal, and either the process is ignoring or blocking the \fBSIGTTIN\fR signal or the process group is orphaned. This error may also be generated for implementation-dependent reasons. .RE .sp .ne 2 .mk .na \fB\fBEOVERFLOW\fR\fR .ad .RS 13n .rt The file is a regular file and an attempt was made to read at or beyond the offset maximum associated with the corresponding stream. .RE .sp .LP The \fBfgetc()\fR, \fBgetc()\fR, \fBgetc_unlocked()\fR, \fBgetchar()\fR, \fBgetchar_unlocked()\fR, and \fBgetw()\fR functions may fail if: .sp .ne 2 .mk .na \fB\fBENOMEM\fR\fR .ad .RS 10n .rt Insufficient storage space is available. .RE .sp .ne 2 .mk .na \fB\fBENXIO\fR\fR .ad .RS 10n .rt A request was made of a non-existent device, or the request was outside the capabilities of the device. .RE .SH USAGE .sp .LP If the integer value returned by \fBfgetc()\fR, \fBgetc()\fR, \fBgetc_unlocked()\fR, \fBgetchar()\fR, \fBgetchar_unlocked()\fR, and \fBgetw()\fR is stored into a variable of type \fBchar\fR and then compared against the integer constant EOF, the comparison may never succeed, because sign-extension of a variable of type \fBchar\fR on widening to integer is implementation-dependent. .sp .LP The \fBferror\fR(3C) or \fBfeof\fR(3C) functions must be used to distinguish between an error condition and an end-of-file condition. .sp .LP Functions exist for the \fBgetc()\fR, \fBgetc_unlocked()\fR, \fBgetchar()\fR, and \fBgetchar_unlocked()\fR macros. To get the function form, the macro name must be undefined (for example, \fB#undef getc\fR). .sp .LP When the macro forms are used, \fBgetc()\fR and \fBgetc_unlocked()\fR evaluate the \fIstream\fR argument more than once. In particular, \fBgetc(*\fR\fIf++\fR\fB);\fR does not work sensibly. The \fBfgetc()\fR function should be used instead when evaluating the \fIstream\fR argument has side effects. .sp .LP Because of possible differences in word length and byte ordering, files written using \fBgetw()\fR are machine-dependent, and may not be read using \fBgetw()\fR on a different processor. .sp .LP The \fBgetw()\fR function is inherently byte stream-oriented and is not tenable in the context of either multibyte character streams or wide-character streams. Application programmers are recommended to use one of the character-based input functions instead. .SH ATTRIBUTES .sp .LP See \fBattributes\fR(5) for descriptions of the following attributes: .sp .sp .TS tab() box; cw(2.75i) |cw(2.75i) lw(2.75i) |lw(2.75i) . ATTRIBUTE TYPEATTRIBUTE VALUE _ Interface StabilityT{ \fBfgetc()\fR, \fBgetc()\fR, \fBgetc_unlocked()\fR, \fBgetchar()\fR, and \fBgetchar_unlocked()\fR are Standard. T} _ MT-LevelSee \fBNOTES\fR below. .TE .SH SEE ALSO .sp .LP \fBIntro\fR(3), \fB__fsetlocking\fR(3C), \fBfclose\fR(3C), \fBfeof\fR(3C), \fBfgets\fR(3C), \fBfgetwc\fR(3C), \fBfgetws\fR(3C), \fBflockfile\fR(3C), \fBfopen\fR(3C), \fBfread\fR(3C), \fBfscanf\fR(3C), \fBgets\fR(3C), \fBputc\fR(3C), \fBscanf\fR(3C), \fBstdio\fR(3C), \fBungetc\fR(3C), \fBungetwc\fR(3C), \fBattributes\fR(5), \fBstandards\fR(5) .SH NOTES .sp .LP The \fBfgetc()\fR, \fBgetc()\fR, \fBgetchar()\fR, and \fBgetw()\fR routines are MT-Safe in multithreaded applications. The \fBgetc_unlocked()\fR and \fBgetchar_unlocked()\fR routines are unsafe in multithreaded applications.