talloc.3

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talloc_realloc(ctx, ptr, type, 0)  ==> talloc_free(ptr);
.fi
.RE
.PP
The
\fIctx\fR
argument is only used if
\fIptr\fR
is not NULL, otherwise it is ignored\.
.PP
talloc_realloc() returns the new pointer, or NULL on failure\. The call will fail either due to a lack of memory, or because the pointer has more than one parent (see
\(lqtalloc_reference()\(rq)\.
.SS "void *talloc_realloc_size(const void *ctx, void *ptr, size_t size);"
.PP
the talloc_realloc_size() function is useful when the type is not known so the type\-safe talloc_realloc() cannot be used\.
.SS "TYPE *talloc_steal(const void *\fInew_ctx\fR, const TYPE *\fIptr\fR);"
.PP
The talloc_steal() function changes the parent context of a talloc pointer\. It is typically used when the context that the pointer is currently a child of is going to be freed and you wish to keep the memory for a longer time\.
.PP
The talloc_steal() function returns the pointer that you pass it\. It does not have any failure modes\.
.PP
NOTE: It is possible to produce loops in the parent/child relationship if you are not careful with talloc_steal()\. No guarantees are provided as to your sanity or the safety of your data if you do this\.
.SS "TYPE *talloc_move(const void *\fInew_ctx\fR, TYPE **\fIptr\fR);"
.PP
The talloc_move() function is a wrapper around talloc_steal() which zeros the source pointer after the move\. This avoids a potential source of bugs where a programmer leaves a pointer in two structures, and uses the pointer from the old structure after it has been moved to a new one\.
.SS "size_t talloc_total_size(const void *\fIptr\fR);"
.PP
The talloc_total_size() function returns the total size in bytes used by this pointer and all child pointers\. Mostly useful for debugging\.
.PP
Passing NULL is allowed, but it will only give a meaningful result if talloc_enable_leak_report() or talloc_enable_leak_report_full() has been called\.
.SS "size_t talloc_total_blocks(const void *\fIptr\fR);"
.PP
The talloc_total_blocks() function returns the total memory block count used by this pointer and all child pointers\. Mostly useful for debugging\.
.PP
Passing NULL is allowed, but it will only give a meaningful result if talloc_enable_leak_report() or talloc_enable_leak_report_full() has been called\.
.SS "void talloc_report(const void *ptr, FILE *f);"
.PP
The talloc_report() function prints a summary report of all memory used by
\fIptr\fR\. One line of report is printed for each immediate child of ptr, showing the total memory and number of blocks used by that child\.
.PP
You can pass NULL for the pointer, in which case a report is printed for the top level memory context, but only if talloc_enable_leak_report() or talloc_enable_leak_report_full() has been called\.
.SS "void talloc_report_full(const void *\fIptr\fR, FILE *\fIf\fR);"
.PP
This provides a more detailed report than talloc_report()\. It will recursively print the entire tree of memory referenced by the pointer\. References in the tree are shown by giving the name of the pointer that is referenced\.
.PP
You can pass NULL for the pointer, in which case a report is printed for the top level memory context, but only if talloc_enable_leak_report() or talloc_enable_leak_report_full() has been called\.
.SS ""
.HP 28
.BI "void talloc_report_depth_cb(" "const\ void\ *ptr" ", " "int\ depth" ", " "int\ max_depth" ", " "void\ (*callback)(const\ void\ *ptr,\ int\ depth,\ int\ max_depth,\ int\ is_ref,\ void\ *priv)" ", " "void\ *priv" ");"
.PP
This provides a more flexible reports than talloc_report()\. It will recursively call the callback for the entire tree of memory referenced by the pointer\. References in the tree are passed with
\fIis_ref = 1\fR
and the pointer that is referenced\.
.PP
You can pass NULL for the pointer, in which case a report is printed for the top level memory context, but only if talloc_enable_leak_report() or talloc_enable_leak_report_full() has been called\.
.PP
The recursion is stopped when depth >= max_depth\. max_depth = \-1 means only stop at leaf nodes\.
.SS ""
.HP 30
.BI "void talloc_report_depth_file(" "const\ void\ *ptr" ", " "int\ depth" ", " "int\ max_depth" ", " "FILE\ *f" ");"
.PP
This provides a more flexible reports than talloc_report()\. It will let you specify the depth and max_depth\.
.SS "void talloc_enable_leak_report(void);"
.PP
This enables calling of talloc_report(NULL, stderr) when the program exits\. In Samba4 this is enabled by using the \-\-leak\-report command line option\.
.PP
For it to be useful, this function must be called before any other talloc function as it establishes a "null context" that acts as the top of the tree\. If you don\'t call this function first then passing NULL to talloc_report() or talloc_report_full() won\'t give you the full tree printout\.
.PP
Here is a typical talloc report:
.sp
.RS 4
.nf
talloc report on \'null_context\' (total 267 bytes in 15 blocks)
libcli/auth/spnego_parse\.c:55  contains   31 bytes in   2 blocks
libcli/auth/spnego_parse\.c:55  contains   31 bytes in   2 blocks
iconv(UTF8,CP850)              contains   42 bytes in   2 blocks
libcli/auth/spnego_parse\.c:55  contains   31 bytes in   2 blocks
iconv(CP850,UTF8)              contains   42 bytes in   2 blocks
iconv(UTF8,UTF\-16LE)           contains   45 bytes in   2 blocks
iconv(UTF\-16LE,UTF8)           contains   45 bytes in   2 blocks
      
.fi
.RE
.SS "void talloc_enable_leak_report_full(void);"
.PP
This enables calling of talloc_report_full(NULL, stderr) when the program exits\. In Samba4 this is enabled by using the \-\-leak\-report\-full command line option\.
.PP
For it to be useful, this function must be called before any other talloc function as it establishes a "null context" that acts as the top of the tree\. If you don\'t call this function first then passing NULL to talloc_report() or talloc_report_full() won\'t give you the full tree printout\.
.PP
Here is a typical full report:
.sp
.RS 4
.nf
full talloc report on \'root\' (total 18 bytes in 8 blocks)
p1               contains     18 bytes in   7 blocks (ref 0)
    r1               contains     13 bytes in   2 blocks (ref 0)
        reference to: p2
    p2               contains      1 bytes in   1 blocks (ref 1)
    x3               contains      1 bytes in   1 blocks (ref 0)
    x2               contains      1 bytes in   1 blocks (ref 0)
    x1               contains      1 bytes in   1 blocks (ref 0)
      
.fi
.RE
.SS "(\fItype\fR *)talloc_zero(const void *\fIctx\fR, \fItype\fR);"
.PP
The talloc_zero() macro is equivalent to:
.sp
.RS 4
.nf
ptr = talloc(ctx, type);
if (ptr) memset(ptr, 0, sizeof(type));
.fi
.RE
.SS "void *talloc_zero_size(const void *\fIctx\fR, size_t \fIsize\fR)"
.PP
The talloc_zero_size() function is useful when you don\'t have a known type\.
.SS "void *talloc_memdup(const void *\fIctx\fR, const void *\fIp\fR, size_t size);"
.PP
The talloc_memdup() function is equivalent to:
.sp
.RS 4
.nf
ptr = talloc_size(ctx, size);
if (ptr) memcpy(ptr, p, size);
.fi
.RE
.SS "char *talloc_strdup(const void *\fIctx\fR, const char *\fIp\fR);"
.PP
The talloc_strdup() function is equivalent to:
.sp
.RS 4
.nf
ptr = talloc_size(ctx, strlen(p)+1);
if (ptr) memcpy(ptr, p, strlen(p)+1);
.fi
.RE
.PP
This function sets the name of the new pointer to the passed string\. This is equivalent to:
.sp
.RS 4
.nf
talloc_set_name_const(ptr, ptr)
.fi
.RE
.SS "char *talloc_strndup(const void *\fIt\fR, const char *\fIp\fR, size_t \fIn\fR);"
.PP
The talloc_strndup() function is the talloc equivalent of the C library function strndup(3)\.
.PP
This function sets the name of the new pointer to the passed string\. This is equivalent to:
.sp
.RS 4
.nf
talloc_set_name_const(ptr, ptr)
.fi
.RE
.SS "char *talloc_append_string(const void *\fIt\fR, char *\fIorig\fR, const char *\fIappend\fR);"
.PP
The talloc_append_string() function appends the given formatted string to the given string\.
.PP
This function sets the name of the new pointer to the new string\. This is equivalent to:
.sp
.RS 4
.nf
talloc_set_name_const(ptr, ptr)
.fi
.RE
.SS "char *talloc_vasprintf(const void *\fIt\fR, const char *\fIfmt\fR, va_list \fIap\fR);"
.PP
The talloc_vasprintf() function is the talloc equivalent of the C library function vasprintf(3)\.
.PP
This function sets the name of the new pointer to the new string\. This is equivalent to:
.sp
.RS 4
.nf
talloc_set_name_const(ptr, ptr)
.fi
.RE
.SS "char *talloc_asprintf(const void *\fIt\fR, const char *\fIfmt\fR, \.\.\.);"
.PP
The talloc_asprintf() function is the talloc equivalent of the C library function asprintf(3)\.
.PP
This function sets the name of the new pointer to the passed string\. This is equivalent to:
.sp
.RS 4
.nf
talloc_set_name_const(ptr, ptr)
.fi
.RE
.SS "char *talloc_asprintf_append(char *s, const char *fmt, \.\.\.);"
.PP
The talloc_asprintf_append() function appends the given formatted string to the given string\.
.PP
This function sets the name of the new pointer to the new string\. This is equivalent to:
.sp
.RS 4
.nf
talloc_set_name_const(ptr, ptr)
.fi
.RE
.SS "(type *)talloc_array(const void *ctx, type, uint_t count);"
.PP
The talloc_array() macro is equivalent to:
.sp
.RS 4
.nf
(type *)talloc_size(ctx, sizeof(type) * count);
.fi
.RE
.PP
except that it provides integer overflow protection for the multiply, returning NULL if the multiply overflows\.
.SS "void *talloc_array_size(const void *ctx, size_t size, uint_t count);"
.PP
The talloc_array_size() function is useful when the type is not known\. It operates in the same way as talloc_array(), but takes a size instead of a type\.
.SS "(typeof(ptr)) talloc_array_ptrtype(const void *ctx, ptr, uint_t count);"
.PP
The talloc_ptrtype() macro should be used when you have a pointer to an array and want to allocate memory of an array to point at with this pointer\. When compiling with gcc >= 3 it is typesafe\. Note this is a wrapper of talloc_array_size() and talloc_get_name() will return the current location in the source file\. and not the type\.
.SS "void *talloc_realloc_fn(const void *ctx, void *ptr, size_t size)"
.PP
This is a non\-macro version of talloc_realloc(), which is useful as libraries sometimes want a realloc function pointer\. A realloc(3) implementation encapsulates the functionality of malloc(3), free(3) and realloc(3) in one call, which is why it is useful to be able to pass around a single function pointer\.
.SS "void *talloc_autofree_context(void);"
.PP
This is a handy utility function that returns a talloc context which will be automatically freed on program exit\. This can be used to reduce the noise in memory leak reports\.
.SS "void *talloc_check_name(const void *ptr, const char *name);"
.PP
This function checks if a pointer has the specified
\fIname\fR\. If it does then the pointer is returned\. It it doesn\'t then NULL is returned\.
.SS "(type *)talloc_get_type(const void *ptr, type);"
.PP
This macro allows you to do type checking on talloc pointers\. It is particularly useful for void* private pointers\. It is equivalent to this:
.sp
.RS 4
.nf
(type *)talloc_check_name(ptr, #type)
.fi
.RE
.SS "talloc_set_type(const void *ptr, type);"
.PP
This macro allows you to force the name of a pointer to be a particular
\fItype\fR\. This can be used in conjunction with talloc_get_type() to do type checking on void* pointers\.
.PP
It is equivalent to this:
.sp
.RS 4
.nf
talloc_set_name_const(ptr, #type)
.fi
.RE
.SH "PERFORMANCE"
.PP
All the additional features of talloc(3) over malloc(3) do come at a price\. We have a simple performance test in Samba4 that measures talloc() versus malloc() performance, and it seems that talloc() is about 10% slower than malloc() on my x86 Debian Linux box\. For Samba, the great reduction in code complexity that we get by using talloc makes this worthwhile, especially as the total overhead of talloc/malloc in Samba is already quite small\.
.SH "SEE ALSO"
.PP
malloc(3), strndup(3), vasprintf(3), asprintf(3),
\fI\%http://talloc.samba.org/\fR
.SH "COPYRIGHT/LICENSE"
.PP
Copyright (C) Andrew Tridgell 2004
.PP
This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version\.
.PP
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE\. See the GNU General Public License for more details\.
.PP
You should have received a copy of the GNU General Public License along with this program; if not, see http://www\.gnu\.org/licenses/\.