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Full Discussion: Help with malloc()
Top Forums UNIX for Dummies Questions & Answers Help with malloc() Post 302775729 by Don Cragun on Tuesday 5th of March 2013 10:28:06 AM
Old 03-05-2013
Quote:
Originally Posted by shamrock
Because the second argument of fgets is an integer while malloc returns pointer to void so take it out...
The problem is much deeper than that.

The given program allocates enough space to hold a pointer to a character; not enough space to read a line of user input. And, I don't see how eracav can preallocate space for "unlimited input from the user". In addition to that, eracav isn't checking the return value of malloc() to determine if space was allocated nor of fgets() to determine if an error or EOF has been encountered before a <newline> was found.

To do what needs to be done, eracav will need much more complicated logic with a loop calling fgets() and realloc() to increase the input buffer size until a <newline> or EOF has been copied into the growing buffer.

Is this a homework assignment?
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MALLOC_GET_STATE(3)					     Linux Programmer's Manual					       MALLOC_GET_STATE(3)

NAME
malloc_get_state, malloc_set_state - record and restore state of malloc implementation SYNOPSIS
#include <malloc.h> void* malloc_get_state(void); int malloc_set_state(void *state); DESCRIPTION
The malloc_get_state() function records the current state of all malloc(3) internal bookkeeping variables (but not the actual contents of the heap or the state of malloc_hook(3) functions pointers). The state is recorded in a system-dependent opaque data structure dynamically allocated via malloc(3), and a pointer to that data structure is returned as the function result. (It is the caller's responsibility to free(3) this memory.) The malloc_set_state() function restores the state of all malloc(3) internal bookkeeping variables to the values recorded in the opaque data structure pointed to by state. RETURN VALUE
On success, malloc_get_state() returns a pointer to a newly allocated opaque data structure. On error (for example, memory could not be allocated for the data structure), malloc_get_state() returns NULL. On success, malloc_set_state() returns 0. If the implementation detects that state does not point to a correctly formed data structure, malloc_set_state() returns -1. If the implementation detects that the version of the data structure referred to by state is a more recent version than this implementation knows about, malloc_set_state() returns -2. CONFORMING TO
These functions are GNU extensions. NOTES
These functions are useful when using this malloc(3) implementation as part of a shared library, and the heap contents are saved/restored via some other method. This technique is used by GNU Emacs to implement its "dumping" function. Hook function pointers are never saved or restored by these functions, with two exceptions: if malloc checking (see mallopt(3)) was in use when malloc_get_state() was called, then malloc_set_state() resets malloc checking hooks if possible; if malloc checking was not in use in the recorded state, but the caller has requested malloc checking, then the hooks are reset to 0. SEE ALSO
malloc(3), mallopt(3) GNU
2014-06-13 MALLOC_GET_STATE(3)
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