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diff --git a/man/man7/system_data_types.7 b/man/man7/system_data_types.7 new file mode 100644 index 0000000..b2dff72 --- /dev/null +++ b/man/man7/system_data_types.7 @@ -0,0 +1,242 @@ +.\" Copyright (c) 2020 by Alejandro Colomar <alx@kernel.org> +.\" and Copyright (c) 2020 by Michael Kerrisk <mtk.manpages@gmail.com> +.\" +.\" SPDX-License-Identifier: Linux-man-pages-copyleft +.\" +.\" +.TH system_data_types 7 2024-05-02 "Linux man-pages (unreleased)" +.SH NAME +system_data_types \- overview of system data types +.SH DESCRIPTION +.\" Layout: +.\" A list of type names (the struct/union keyword will be omitted). +.\" Each entry will have the following parts: +.\" * Include (see NOTES) +.\" +.\" * Definition (no "Definition" header) +.\" Only struct/union types will have definition; +.\" typedefs will remain opaque. +.\" +.\" * Description (no "Description" header) +.\" A few lines describing the type. +.\" +.\" * Versions (optional) +.\" +.\" * Conforming to (see NOTES) +.\" Format: CXY and later; POSIX.1-XXXX and later. +.\" +.\" * Notes (optional) +.\" +.\" * Bugs (if any) +.\" +.\" * See also +.\"------------------------------------- aiocb ------------------------/ +.\"------------------------------------- blkcnt_t ---------------------/ +.\"------------------------------------- blksize_t --------------------/ +.\"------------------------------------- cc_t -------------------------/ +.\"------------------------------------- clock_t ----------------------/ +.\"------------------------------------- clockid_t --------------------/ +.\"------------------------------------- dev_t ------------------------/ +.\"------------------------------------- div_t ------------------------/ +.\"------------------------------------- double_t ---------------------/ +.\"------------------------------------- fd_set -----------------------/ +.\"------------------------------------- fenv_t -----------------------/ +.\"------------------------------------- fexcept_t --------------------/ +.\"------------------------------------- FILE -------------------------/ +.\"------------------------------------- float_t ----------------------/ +.\"------------------------------------- gid_t ------------------------/ +.\"------------------------------------- id_t -------------------------/ +.\"------------------------------------- imaxdiv_t --------------------/ +.\"------------------------------------- intmax_t ---------------------/ +.\"------------------------------------- intN_t -----------------------/ +.\"------------------------------------- intptr_t ---------------------/ +.\"------------------------------------- lconv ------------------------/ +.\"------------------------------------- ldiv_t -----------------------/ +.\"------------------------------------- lldiv_t ----------------------/ +.\"------------------------------------- mode_t -----------------------/ +.\"------------------------------------- off64_t ----------------------/ +.\"------------------------------------- off_t ------------------------/ +.\"------------------------------------- pid_t ------------------------/ +.\"------------------------------------- ptrdiff_t --------------------/ +.\"------------------------------------- regex_t ----------------------/ +.\"------------------------------------- regmatch_t -------------------/ +.\"------------------------------------- regoff_t ---------------------/ +.\"------------------------------------- sigevent ---------------------/ +.\"------------------------------------- siginfo_t --------------------/ +.TP +.I siginfo_t +.RS +.IR Include : +.IR <signal.h> . +Alternatively, +.IR <sys/wait.h> . +.P +.EX +typedef struct { + int si_signo; /* Signal number */ + int si_code; /* Signal code */ + pid_t si_pid; /* Sending process ID */ + uid_t si_uid; /* Real user ID of sending process */ + void *si_addr; /* Memory location which caused fault */ + int si_status; /* Exit value or signal */ + union sigval si_value; /* Signal value */ +} siginfo_t; +.EE +.P +Information associated with a signal. +For further details on this structure +(including additional, Linux-specific fields), see +.BR sigaction (2). +.P +.IR "Conforming to" : +POSIX.1-2001 and later. +.P +.IR "See also" : +.BR pidfd_send_signal (2), +.BR rt_sigqueueinfo (2), +.BR sigaction (2), +.BR sigwaitinfo (2), +.BR psiginfo (3) +.RE +.\"------------------------------------- sigset_t ---------------------/ +.TP +.I sigset_t +.RS +.IR Include : +.IR <signal.h> . +Alternatively, +.IR <spawn.h> , +or +.IR <sys/select.h> . +.P +This is a type that represents a set of signals. +According to POSIX, this shall be an integer or structure type. +.P +.IR "Conforming to" : +POSIX.1-2001 and later. +.P +.IR "See also" : +.BR epoll_pwait (2), +.BR ppoll (2), +.BR pselect (2), +.BR sigaction (2), +.BR signalfd (2), +.BR sigpending (2), +.BR sigprocmask (2), +.BR sigsuspend (2), +.BR sigwaitinfo (2), +.BR signal (7) +.RE +.\"------------------------------------- sigval -----------------------/ +.\"------------------------------------- size_t -----------------------/ +.\"------------------------------------- sockaddr ---------------------/ +.\"------------------------------------- socklen_t --------------------/ +.\"------------------------------------- ssize_t ----------------------/ +.\"------------------------------------- stat -------------------------/ +.\"------------------------------------- suseconds_t ------------------/ +.\"------------------------------------- time_t -----------------------/ +.\"------------------------------------- timer_t ----------------------/ +.\"------------------------------------- timespec ---------------------/ +.\"------------------------------------- timeval ----------------------/ +.\"------------------------------------- uid_t ----------------------/ +.\"------------------------------------- uintmax_t --------------------/ +.\"------------------------------------- uintN_t ----------------------/ +.\"------------------------------------- uintptr_t --------------------/ +.\"------------------------------------- useconds_t -------------------/ +.\"------------------------------------- va_list ----------------------/ +.\"------------------------------------- void * -----------------------/ +.\"--------------------------------------------------------------------/ +.SH NOTES +The structures described in this manual page shall contain, +at least, the members shown in their definition, in no particular order. +.P +Most of the integer types described in this page don't have +a corresponding length modifier for the +.BR printf (3) +and the +.BR scanf (3) +families of functions. +To print a value of an integer type that doesn't have a length modifier, +it should be converted to +.I intmax_t +or +.I uintmax_t +by an explicit cast. +To scan into a variable of an integer type +that doesn't have a length modifier, +an intermediate temporary variable of type +.I intmax_t +or +.I uintmax_t +should be used. +When copying from the temporary variable to the destination variable, +the value could overflow. +If the type has upper and lower limits, +the user should check that the value is within those limits, +before actually copying the value. +The example below shows how these conversions should be done. +.SS Conventions used in this page +In "Conforming to" we only concern ourselves with +C99 and later and POSIX.1-2001 and later. +Some types may be specified in earlier versions of one of these standards, +but in the interests of simplicity we omit details from earlier standards. +.P +In "Include", we first note the "primary" header(s) that +define the type according to either the C or POSIX.1 standards. +Under "Alternatively", we note additional headers that +the standards specify shall define the type. +.SH EXAMPLES +The program shown below scans from a string and prints a value stored in +a variable of an integer type that doesn't have a length modifier. +The appropriate conversions from and to +.IR intmax_t , +and the appropriate range checks, +are used as explained in the notes section above. +.P +.EX +#include <stdint.h> +#include <stdio.h> +#include <stdlib.h> +#include <sys/types.h> +\& +int +main (void) +{ + static const char *const str = "500000 us in half a second"; + suseconds_t us; + intmax_t tmp; +\& + /* Scan the number from the string into the temporary variable. */ +\& + sscanf(str, "%jd", &tmp); +\& + /* Check that the value is within the valid range of suseconds_t. */ +\& + if (tmp < \-1 || tmp > 1000000) { + fprintf(stderr, "Scanned value outside valid range!\en"); + exit(EXIT_FAILURE); + } +\& + /* Copy the value to the suseconds_t variable \[aq]us\[aq]. */ +\& + us = tmp; +\& + /* Even though suseconds_t can hold the value \-1, this isn\[aq]t + a sensible number of microseconds. */ +\& + if (us < 0) { + fprintf(stderr, "Scanned value shouldn\[aq]t be negative!\en"); + exit(EXIT_FAILURE); + } +\& + /* Print the value. */ +\& + printf("There are %jd microseconds in half a second.\en", + (intmax_t) us); +\& + exit(EXIT_SUCCESS); +} +.EE +.SH SEE ALSO +.BR feature_test_macros (7), +.BR standards (7) |