diff options
Diffstat (limited to 'pod/perlfunc.pod')
| -rw-r--r-- | pod/perlfunc.pod | 74 |
1 files changed, 50 insertions, 24 deletions
diff --git a/pod/perlfunc.pod b/pod/perlfunc.pod index cba3f2a35f..e8dc893efa 100644 --- a/pod/perlfunc.pod +++ b/pod/perlfunc.pod @@ -108,8 +108,8 @@ delete, each, exists, keys, values binmode, close, closedir, dbmclose, dbmopen, die, eof, fileno, flock, format, getc, print, printf, read, readdir, -rewinddir, seek, seekdir, select, syscall, sysread, -syswrite, tell, telldir, truncate, warn, write +rewinddir, seek, seekdir, select, syscall, sysread, sysseek, +systell, syswrite, tell, telldir, truncate, warn, write =item Functions for fixed length data or records @@ -2096,17 +2096,29 @@ follows: c A signed char value. C An unsigned char value. + s A signed short value. S An unsigned short value. + (This 'short' is _exactly_ 16 bits, which may differ from + what a local C compiler calls 'short'.) + i A signed integer value. I An unsigned integer value. + (This 'integer' is _at_least_ 32 bits wide. Its exact size + depends on what a local C compiler calls 'int', and may + even be larger than the 'long' described in the next item.) + l A signed long value. L An unsigned long value. + (This 'long' is _exactly_ 32 bits, which may differ from + what a local C compiler calls 'long'.) - n A short in "network" order. - N A long in "network" order. + n A short in "network" (big-endian) order. + N A long in "network" (big-endian) order. v A short in "VAX" (little-endian) order. V A long in "VAX" (little-endian) order. + (These 'shorts' and 'longs' are _exactly_ 16 bits and + _exactly_ 32 bits, respectively.) f A single-precision float in the native format. d A double-precision float in the native format. @@ -2116,10 +2128,10 @@ follows: u A uuencoded string. - w A BER compressed integer. Bytes give an unsigned integer base - 128, most significant digit first, with as few digits as - possible, and with the bit 8 of each byte except the last set - to "1." + w A BER compressed integer. Its bytes represent an unsigned + integer in base 128, most significant digit first, with as few + digits as possible. Bit eight (the high bit) is set on each + byte except the last. x A null byte. X Back up a byte. @@ -3330,11 +3342,12 @@ into that kind of thing. =item sysread FILEHANDLE,SCALAR,LENGTH Attempts to read LENGTH bytes of data into variable SCALAR from the -specified FILEHANDLE, using the system call read(2). It bypasses -stdio, so mixing this with other kinds of reads or with seek() may -cause confusion. Returns the number of bytes actually read, or undef -if there was an error. SCALAR will be grown or shrunk so that the -last byte actually read is the last byte of the scalar after the read. +specified FILEHANDLE, using the system call read(2). It bypasses stdio, +so mixing this with other kinds of reads, print(), write(), seek(), or +tell() can cause confusion. Returns the number of bytes actually read, +or undef if there was an error. SCALAR will be grown or shrunk so that +the last byte actually read is the last byte of the scalar after the +read. An OFFSET may be specified to place the read data at some place in the string other than the beginning. A negative OFFSET specifies @@ -3346,13 +3359,25 @@ the result of the read is appended. =item sysseek FILEHANDLE,POSITION,WHENCE Randomly positions the system file pointer for FILEHANDLE using the -system call lseek(2). It bypasses stdio, so mixing this with read(), -print(), write(), or seek() may cause confusion. FILEHANDLE may be an -expression whose value gives the name of the filehandle. The values for -WHENCE are 0 to set the file pointer to POSITION, 1 to set the it to -current plus POSITION, and 2 to set it to EOF plus offset. You may use -the values SEEK_SET, SEEK_CUR, and SEEK_END for this from either the -IO::Seekable or the POSIX module. Returns 1 upon success, 0 otherwise. +system call lseek(2). It bypasses stdio, so mixing this with reads +(other than sysread()), print(), write(), seek(), or tell() may cause +confusion. FILEHANDLE may be an expression whose value gives the name +of the filehandle. The values for WHENCE are 0 to set the file pointer +to POSITION, 1 to set the it to current plus POSITION, and 2 to set it +to EOF plus offset. You may use the values SEEK_SET, SEEK_CUR, and +SEEK_END for this from either the IO::Seekable or the POSIX module. +Returns 1 upon success, 0 otherwise. See also L</systell>. + +=item systell FILEHANDLE + +=item systell + +Returns the current position of the system file pointer for FILEHANDLE +as reported by the system call lseek(2). It bypasses stdio, so mixing +this with reads (other than sysread()), print(), write(), seek(), or +tell() may cause confusion. FILEHANDLE may be an expression whose value +gives the name of the actual filehandle. If FILEHANDLE is omitted, +assumes the file last read. See also L</sysseek>. =item system LIST @@ -3404,10 +3429,11 @@ signals and core dumps. Attempts to write LENGTH bytes of data from variable SCALAR to the specified FILEHANDLE, using the system call write(2). It bypasses -stdio, so mixing this with prints or with seek() may cause confusion. -Returns the number of bytes actually written, or undef if there was an -error. If the length is greater than the available data, only as much -data as is available will be written. +stdio, so mixing this with reads (other than sysread()), print(), +write(), seek(), or tell() may cause confusion. Returns the number of +bytes actually written, or undef if there was an error. If the length +is greater than the available data, only as much data as is available +will be written. An OFFSET may be specified to write the data from some part of the string other than the beginning. A negative OFFSET specifies writing |