103 lines
2.8 KiB
Groff
103 lines
2.8 KiB
Groff
.TH ALLOC 3ACK "March 25, 1986"
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.ad
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.SH NAME
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Malloc, Salloc, Realloc, Srealloc, st_alloc, st_free\ \-\ low level memory allocation routines
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.SH SYNOPSIS
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.B #include <alloc.h>
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.PP
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.B char *Malloc(size)
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.br
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.B unsigned int size;
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.PP
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.B char *Salloc(str, size)
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.br
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.B char *str;
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.B unsigned int size;
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.PP
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.B char *Realloc(ptr, size)
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.B char *buf;
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.B unsigned int size;
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.PP
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.B char *Srealloc(str, size)
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.br
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.B char *str;
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.br
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.B unsigned int size;
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.PP
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.B char *st_alloc(phead, size, count)
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.br
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.B char **phead;
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.br
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.B unsigned int size;
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.PP
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.B st_free(ptr, phead, size)
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.br
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.B char *ptr;
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.br
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.B char **phead;
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.br
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.B unsigned int size;
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.PP
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.br
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.B clear(ptr, size)
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.br
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.B char *ptr;
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.br
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.B unsigned int size;
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.PP
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.SH DESCRIPTION
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This set of routines provides a checking memory allocation mechanism.
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.PP
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\fIMalloc\fR returns a pointer to a block of at least \fIsize\fR
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bytes, beginning on a boundary suitable for any data type.
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.PP
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\fISalloc\fR returns a pointer to a block of at least \fIsize\fR
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bytes, initialized with the null-terminated string \fIstr\fR.
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.PP
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\fIRealloc\fR changes the size of
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the block at \fIbuf\fR to \fIsize\fR bytes, and returns a pointer to the
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(possibly moved) block.
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.PP
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\fISrealloc\fR reallocates
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the string at \fIstr\fR to \fIsize\fR bytes.
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It actually does the same as \fIRealloc\fP, and exists only for
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backwards compatibility.
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.PP
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All these routines use \fImalloc\fR and \fIrealloc\fR.
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\fIFree\fR can be used on pointers returned by these routines.
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.PP
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\fISt_alloc\fR and \fIst_free\fR provide a mechanism for maintaining free lists
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of structures.
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\fISt_alloc\fR takes three parameters: \fIphead\fR is a pointer to a field
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containing the head of the free list, \fIsize\fR contains the size of the
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structures, and \fIcount\fR indicates how many new structures must be allocated
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in case the free list is exhausted.
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It returns a pointer to a zero-initialized structure.
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\fISt_free\fR also takes three parameters: \fIptr\fR is a pointer to
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the structure to be freed, \fIphead\fR is again a pointer to a field
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containing the head of the free list, and \fIsize\fR again contains the size
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of the structures.
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These last two routines are best used in a macro.
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.PP
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\fIClear\fR clears \fIsize\fR bytes, starting at \fIptr\fR.
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.SH FILES
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.nf
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~em/modules/h/alloc.h
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~em/modules/lib/liballoc.a
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.fi
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.SH "SEE ALSO"
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malloc(3)
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.SH DIAGNOSTICS
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\fIMalloc\fR, \fISalloc\fR, \fIRealloc\fP, \fISrealloc\fR, and \fIst_alloc\fR
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call a routine \fINo_Mem\fR if there is no memory available. This routine
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is not supposed to return. A default one, that
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gives an error message and stops execution, is provided.
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.SH BUGS
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The
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.I st_alloc
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mechanism only works for structures that are large enough to contain one
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pointer.
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Also,
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.I st_free
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actually is a macro, and references its arguments more than once, so they
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better not have side-effects.
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