diff options
Diffstat (limited to 'newlib/libc/sys.tex')
| -rw-r--r-- | newlib/libc/sys.tex | 123 |
1 files changed, 42 insertions, 81 deletions
diff --git a/newlib/libc/sys.tex b/newlib/libc/sys.tex index 3b04c1500..3182b71c5 100644 --- a/newlib/libc/sys.tex +++ b/newlib/libc/sys.tex @@ -34,7 +34,7 @@ Graceful failure is permitted by returning an error code. A minor complication arises here: the C library must be compatible with development environments that supply fully functional versions of these subroutines. Such environments usually return error codes in a global -@code{errno}. However, the Red Hat newlib C library provides a @emph{macro} +@code{errno}. However, the Cygnus C library provides a @emph{macro} definition for @code{errno} in the header file @file{errno.h}, as part of its support for reentrant routines (@pxref{Reentrancy,,Reentrancy}). @@ -68,8 +68,8 @@ it (@code{exit}, @code{system}). Close a file. Minimal implementation: @example -int close(int file) @{ - return -1; +int close(int file)@{ + return -1; @} @end example @@ -90,8 +90,8 @@ without processes): #include <errno.h> #undef errno extern int errno; -int execve(char *name, char **argv, char **env) @{ - errno = ENOMEM; +int execve(char *name, char **argv, char **env)@{ + errno=ENOMEM; return -1; @} @end example @@ -103,8 +103,8 @@ Create a new process. Minimal implementation (for a system without processes): #include <errno.h> #undef errno extern int errno; -int fork(void) @{ - errno = EAGAIN; +int fork() @{ + errno=EAGAIN; return -1; @} @end example @@ -129,7 +129,7 @@ conflict with other processes. Minimal implementation, for a system without processes: @example -int getpid(void) @{ +int getpid() @{ return 1; @} @end example @@ -140,8 +140,8 @@ other minimal implementations, which only support output to @code{stdout}, this minimal implementation is suggested: @example -int isatty(int file) @{ - return 1; +int isatty(int file)@{ + return 1; @} @end example @@ -152,9 +152,9 @@ Send a signal. Minimal implementation: #include <errno.h> #undef errno extern int errno; -int kill(int pid, int sig) @{ - errno = EINVAL; - return -1; +int kill(int pid, int sig)@{ + errno=EINVAL; + return(-1); @} @end example @@ -165,8 +165,8 @@ Establish a new name for an existing file. Minimal implementation: #include <errno.h> #undef errno extern int errno; -int link(char *old, char *new) @{ - errno = EMLINK; +int link(char *old, char *new)@{ + errno=EMLINK; return -1; @} @end example @@ -175,26 +175,19 @@ int link(char *old, char *new) @{ Set position in a file. Minimal implementation: @example -int lseek(int file, int ptr, int dir) @{ - return 0; +int lseek(int file, int ptr, int dir)@{ + return 0; @} @end example -@item open -Open a file. Minimal implementation: - -@example -int open(const char *name, int flags, int mode) @{ - return -1; -@} -@end example +@c FIXME! Why no stub for open? @item read Read from a file. Minimal implementation: @example -int read(int file, char *ptr, int len) @{ - return 0; +int read(int file, char *ptr, int len)@{ + return 0; @} @end example @@ -202,23 +195,24 @@ int read(int file, char *ptr, int len) @{ Increase program data space. As @code{malloc} and related functions depend on this, it is useful to have a working implementation. The following suffices for a standalone system; it exploits the symbol -@code{_end} automatically defined by the GNU linker. +@code{end} automatically defined by the GNU linker. @example @group -caddr_t sbrk(int incr) @{ - extern char _end; /* @r{Defined by the linker} */ +caddr_t sbrk(int incr)@{ + extern char end; /* @r{Defined by the linker} */ static char *heap_end; char *prev_heap_end; if (heap_end == 0) @{ - heap_end = &_end; + heap_end = &end; @} prev_heap_end = heap_end; - if (heap_end + incr > stack_ptr) @{ - write (1, "Heap and stack collision\n", 25); - abort (); - @} + if (heap_end + incr > stack_ptr) + @{ + _write (1, "Heap and stack collision\n", 25); + abort (); + @} heap_end += incr; return (caddr_t) prev_heap_end; @@ -240,7 +234,7 @@ int stat(char *file, struct stat *st) @{ Timing information for current process. Minimal implementation: @example -int times(struct tms *buf) @{ +int times(struct tms *buf)@{ return -1; @} @end example @@ -252,8 +246,8 @@ Remove a file's directory entry. Minimal implementation: #include <errno.h> #undef errno extern int errno; -int unlink(char *name) @{ - errno = ENOENT; +int unlink(char *name)@{ + errno=ENOENT; return -1; @} @end example @@ -265,30 +259,30 @@ Wait for a child process. Minimal implementation: #undef errno extern int errno; int wait(int *status) @{ - errno = ECHILD; + errno=ECHILD; return -1; @} @end example @item write -Write to a file. @file{libc} subroutines will use this +Write a character to a file. @file{libc} subroutines will use this system routine for output to all files, @emph{including} @code{stdout}---so if you need to generate any output, for example to a serial port for debugging, you should make your minimal @code{write} capable of doing this. The following minimal implementation is an -incomplete example; it relies on a @code{outbyte} subroutine (not +incomplete example; it relies on a @code{writechar} subroutine (not shown; typically, you must write this in assembler from examples provided by your hardware manufacturer) to actually perform the output. @example @group -int write(int file, char *ptr, int len) @{ - int todo; - - for (todo = 0; todo < len; todo++) @{ - outbyte (*ptr++); - @} - return len; +int write(int file, char *ptr, int len)@{ + int todo; + + for (todo = 0; todo < len; todo++) @{ + writechar(*ptr++); + @} + return len; @} @end group @end example @@ -347,17 +341,6 @@ int _open_r(void *@var{reent}, const char *@var{file}, int @var{flags}, int @var{mode}); @end example -@ifset STDIO64 -@item _open64_r -A reentrant version of @code{open64}. It takes a pointer -to the global data block, which holds @code{errno}. - -@example -int _open64_r(void *@var{reent}, - const char *@var{file}, int @var{flags}, int @var{mode}); -@end example -@end ifset - @item _close_r A reentrant version of @code{close}. It takes a pointer to the global data block, which holds @code{errno}. @@ -375,17 +358,6 @@ off_t _lseek_r(void *@var{reent}, int @var{fd}, off_t @var{pos}, int @var{whence}); @end example -@ifset STDIO64 -@item _lseek64_r -A reentrant version of @code{lseek64}. It takes a pointer to the global -data block, which holds @code{errno}. - -@example -off_t _lseek64_r(void *@var{reent}, - int @var{fd}, off_t @var{pos}, int @var{whence}); -@end example -@end ifset - @item _read_r A reentrant version of @code{read}. It takes a pointer to the global data block, which holds @code{errno}. @@ -438,17 +410,6 @@ int _fstat_r(void *@var{reent}, int @var{fd}, struct stat *@var{pstat}); @end example -@ifset STDIO64 -@item _fstat64_r -A reentrant version of @code{fstat64}. It takes a pointer to the global -data block, which holds @code{errno}. - -@example -int _fstat64_r(void *@var{reent}, - int @var{fd}, struct stat *@var{pstat}); -@end example -@end ifset - @item _link_r A reentrant version of @code{link}. It takes a pointer to the global data block, which holds @code{errno}. |