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.Dd $Mdocdate: June 5 2013 $ .Dt CONFSTR 3 .Os .Sh NAME .Nm confstr .Nd get string-valued configurable variables .Sh SYNOPSIS n unistd.h .Ft size_t .Fn confstr "int name" "char *buf" "size_t len" .Sh DESCRIPTION The .Fn confstr function provides a method for applications to get configuration defined string values.
p The .Fa name argument specifies the system variable to be queried. Symbolic constants for each name value are found in the include file n unistd.h . The .Fa len argument specifies the size of the buffer referenced by the argument .Fa buf . If .Fa len is non-zero, .Fa buf is a non-null pointer, and .Fa name has a value; up to .Fa len - 1 bytes of the value are copied into the buffer .Fa buf . The copied value is always NUL terminated.
p The available values are as follows: l -tag -width "123456" -compact t Li _CS_PATH Return a value for the .Ev PATH environment variable that finds all the standard utilities.
p t Li _CS_V7_ENV Return a space separated list of environment variable assignments (other than .Ev PATH ) necessary for obtaining a shell environment compliant with .St -p1003.1-2008 .
p t Li _CS_V6_ENV Return a space separated list of environment variable assignments (other than .Ev PATH ) necessary for obtaining a shell environment compliant with .St -p1003.1-2001 .
p t Li _CS_POSIX_V7_THREADS_CFLAGS Return the compiler flags for compiling objects in a program that uses multiple threads.
p t Li _CS_POSIX_V7_THREADS_LDFLAGS Return the linker flags for linking an executable that uses multiple threads.
p t Li _CS_POSIX_V7_WIDTH_RESTRICTED_ENVS t Li _CS_POSIX_V6_WIDTH_RESTRICTED_ENVS Return a newline separated list of supported compilation environments in which none of the following types are wider than type .Vt long : .Vt blksize_t , cc_t , mode_t , nfds_t , pid_t , ptrdiff_t , size_t , .Vt speed_t , ssize_t , suseconds_t , tcflag_t , wchar_t , and .Vt wint_t .
p t Li _CS_POSIX_V7_ILP32_OFFBIG_CFLAGS t Li _CS_POSIX_V7_ILP32_OFFBIG_LDFLAGS t Li _CS_POSIX_V7_ILP32_OFFBIG_LIBS t Li _CS_POSIX_V6_ILP32_OFFBIG_CFLAGS t Li _CS_POSIX_V6_ILP32_OFFBIG_LDFLAGS t Li _CS_POSIX_V6_ILP32_OFFBIG_LIBS If .Fn sysconf _SC_V7_ILP32_OFFBIG returns a value greater than zero, return the compiler flags for compiling objects, the linker flags for linking an executable, or the linker arguments for additional libraries, respectively, for a compilation environment with 32-bit .Vt int , long , and .Vt pointer types and an .Vt off_t type that has a width of at least 64 bits. Otherwise, the result is unspecified.
p t Li _CS_POSIX_V7_LP64_OFF64_CFLAGS t Li _CS_POSIX_V7_LP64_OFF64_LDFLAGS t Li _CS_POSIX_V7_LP64_OFF64_LIBS t Li _CS_POSIX_V6_LP64_OFF64_CFLAGS t Li _CS_POSIX_V6_LP64_OFF64_LDFLAGS t Li _CS_POSIX_V6_LP64_OFF64_LIBS If .Fn sysconf _SC_V7_LP64_OFF64 returns a value greater than zero, return the compiler flags for compiling objects, the linker flags for linking an executable, or the linker arguments for additional libraries, respectively, for a compilation environment with 64-bit .Vt int , long , pointer , and .Vt off_t types. Otherwise, the result is unspecified.
p t Li _CS_POSIX_V7_LPBIG_OFFBIG_CFLAGS t Li _CS_POSIX_V7_LPBIG_OFFBIG_LDFLAGS t Li _CS_POSIX_V7_LPBIG_OFFBIG_LIBS t Li _CS_POSIX_V6_LPBIG_OFFBIG_CFLAGS t Li _CS_POSIX_V6_LPBIG_OFFBIG_LDFLAGS t Li _CS_POSIX_V6_LPBIG_OFFBIG_LIBS If .Fn sysconf _SC_V7_LPBIG_OFFBIG returns a value greater than zero, return the compiler flags for compiling objects, the linker flags for linking an executable, or the linker arguments for additional libraries, respectively, for a compilation environment with .Vt int , long , pointer , and .Vt off_t types that all have widths of at least 64 bits. Otherwise, the result is unspecified. .El .Sh RETURN VALUES If the call to .Nm is not successful, 0 is returned and .Va errno is set appropriately. Otherwise, if the variable does not have a configuration defined value, 0 is returned and .Va errno is not modified. Otherwise, the buffer size needed to hold the entire configuration-defined value is returned. If this size is greater than the argument .Fa len , the string in .Fa buf was truncated. .Sh ERRORS The .Nm function will fail if: l -tag -width Er t Bq Er EINVAL The value of the .Fa name argument is invalid. .El .Sh SEE ALSO .Xr pathconf 2 , .Xr sysconf 3 .Sh STANDARDS The .Nm function conforms to .St -p1003.1-2008 . .Sh HISTORY The .Nm function first appeared in x 4.4 .