Home
Main website
Display Sidebar
Hide Ads
Recent Changes
View Source:
perlclib(1)
Edit
PageHistory
Diff
Info
LikePages
PERLCLIB !!!PERLCLIB NAME DESCRIPTION SEE ALSO ---- !!NAME perlclib - Internal replacements for standard C library functions !!DESCRIPTION One thing Perl porters should note is that ''perl'' doesn't tend to use that much of the C standard library internally; you'll see very little use of, for example, the ''ctype.h'' functions in there. This is because Perl tends to reimplement or abstract standard library functions, so that we know exactly how they're going to operate. This is a reference card for people who are familiar with the C library and who want to do things the Perl way; to tell them which functions they ought to use instead of the more normal C functions. __Conventions__ In the following tables: t is a type. p is a pointer. n is a number. s is a string. sv, av, hv, etc. represent variables of their respective types. __File Operations__ Instead of the ''stdio.h'' functions, you should use the Perl abstraction layer. Instead of FILE* types, you need to be handling PerlIO* types. Don't forget that with the new PerlIO layered I/O abstraction FILE* types may not even be available. See also the perlapio documentation for more information about the following functions: Instead Of: Use: stdin PerlIO_stdin() stdout PerlIO_stdout() stderr PerlIO_stderr() fopen(fn, mode) PerlIO_open(fn, mode) freopen(fn, mode, stream) PerlIO_reopen(fn, mode, perlio) (Deprecated) fflush(stream) PerlIO_flush(perlio) fclose(stream) PerlIO_close(perlio) __File Input and Output__ Instead Of: Use: fprintf(stream, fmt, ...) PerlIO_printf(perlio, fmt, ...) [[f]getc(stream) PerlIO_getc(perlio) [[f]putc(stream, n) PerlIO_putc(perlio, n) ungetc(n, stream) PerlIO_ungetc(perlio, n) Note that the PerlIO equivalents of fread and fwrite are slightly different from their C library counterparts: fread(p, size, n, stream) PerlIO_read(perlio, buf, numbytes) fwrite(p, size, n, stream) PerlIO_write(perlio, buf, numbytes) fputs(s, stream) PerlIO_puts(perlio, s) There is no equivalent to fgets; one should use sv_gets instead: fgets(s, n, stream) sv_gets(sv, perlio, append) __File Positioning__ Instead Of: Use: feof(stream) PerlIO_eof(perlio) fseek(stream, n, whence) PerlIO_seek(perlio, n, whence) rewind(stream) PerlIO_rewind(perlio) fgetpos(stream, p) PerlIO_getpos(perlio, sv) fsetpos(stream, p) PerlIO_setpos(perlio, sv) ferror(stream) PerlIO_error(perlio) clearerr(stream) PerlIO_clearerr(perlio) __Memory Management and String Handling__ Instead Of: Use: t* p = malloc(n) New(id, p, n, t) t* p = calloc(n, s) Newz(id, p, n, t) p = realloc(p, n) Renew(p, n, t) memcpy(dst, src, n) Copy(src, dst, n, t) memmove(dst, src, n) Move(src, dst, n, t) memcpy/*(struct foo *) !StructCopy(src, dst, t) free(p) Safefree(p) strdup(p) savepv(p) strndup(p, n) savepvn(p, n) (Hey, strndup doesn't exist!) strstr(big, little) instr(big, little) strcmp(s1, s2) strLE(s1, s2) / strEQ(s1, s2) / strGT(s1,s2) strncmp(s1, s2, n) strnNE(s1, s2, n) / strnEQ(s1, s2, n) Notice the different order of arguments to Copy and Move than used in memcpy and memmove. Most of the time, though, you'll want to be dealing with SVs internally instead of raw char * strings: strlen(s) sv_len(sv) strcpy(dt, src) sv_setpv(sv, s) strncpy(dt, src, n) sv_setpvn(sv, s, n) strcat(dt, src) sv_catpv(sv, s) strncat(dt, src) sv_catpvn(sv, s) sprintf(s, fmt, ...) sv_setpvf(sv, fmt, ...) Note also the existence of sv_catpvf and sv_catpvfn, combining concatenation with formatting. __Character Class Tests__ There are two types of character class tests that Perl implements: one type deals in chars and are thus __not__ Unicode aware (and hence deprecated unless you __know__ you should use them) and the other type deal in UVs and know about Unicode properties. In the following table, c is a char, and u is a Unicode codepoint. Instead Of: Use: But better use: isalnum(c) isALNUM(c) isALNUM_uni(u) isalpha(c) isALPHA(c) isALPHA_uni(u) iscntrl(c) isCNTRL(c) isCNTRL_uni(u) isdigit(c) isDIGIT(c) isDIGIT_uni(u) isgraph(c) isGRAPH(c) isGRAPH_uni(u) islower(c) isLOWER(c) isLOWER_uni(u) isprint(c) isPRINT(c) isPRINT_uni(u) ispunct(c) isPUNCT(c) isPUNCT_uni(u) isspace(c) isSPACE(c) isSPACE_uni(u) isupper(c) isUPPER(c) isUPPER_uni(u) isxdigit(c) isXDIGIT(c) isXDIGIT_uni(u) tolower(c) toLOWER(c) toLOWER_uni(u) toupper(c) toUPPER(c) toUPPER_uni(u) ''stdlib.h'' __functions__ Instead Of: Use: atof(s) Atof(s) atol(s) Atol(s) strtod(s, *p) Nothing. Just don't use it. strtol(s, *p, n) Strtol(s, *p, n) strtoul(s, *p, n) Strtoul(s, *p, n) Notice also the scan_bin, scan_hex, and scan_oct functions in ''util.c'' for converting strings representing numbers in the respective bases into NVs. In theory Strtol and Strtoul may not be defined if the machine perl is built on doesn't actually have strtol and strtoul. But as those 2 functions are part of the 1989 ANSI C spec we suspect you'll find them everywhere by now. int rand() double Drand01() srand(n) { seedDrand01((Rand_seed_t)n); PL_srand_called = TRUE; } exit(n) my_exit(n) system(s) Don't. Look at pp_system or use my_popen getenv(s) !PerlEnv_getenv(s) setenv(s, val) my_putenv(s, val) __Miscellaneous functions__ You should not even __want__ to use ''setjmp.h'' functions, but if you think you do, use the JMPENV stack in ''scope.h'' instead. For signal/sigaction, use rsignal(signo, handler). !!SEE ALSO perlapi, perlapio, perlguts ----
One page links to
perlclib(1)
:
Man1p
This page is a man page (or other imported legacy content). We are unable to automatically determine the license status of this page.
