What does strtol return if fails?
RETURN VALUE top The strtol() function returns the result of the conversion, unless the value would underflow or overflow. If an underflow occurs, strtol() returns LONG_MIN. If an overflow occurs, strtol() returns LONG_MAX. In both cases, errno is set to ERANGE.
Is strtol a system call?
The explain_strtol function is used to obtain an explanation of an error returned by the strtol(3) system call. The least the message will contain is the value of strerror(errno), but usually it will do much better, and indicate the underlying cause in more detail.
What is strtol function in C?
C library function – strtol() The C library function long int strtol(const char *str, char **endptr, int base) converts the initial part of the string in str to a long int value according to the given base, which must be between 2 and 36 inclusive, or be the special value 0.
Does strtol modify the original string?
A pointer to a string to convert to a long integer. It is used by the strtol function to indicate where the conversion stopped. The strtol function will modify endptr (if endptr is not a null pointer) so that endptr points to the first character that was not converted.
Is Atoi safe?
* The atoi function is not thread-safe and also not async-cancel safe. * The atoi function has been deprecated by strtol and should not be used in new code.
Where is strtol defined?
Here is how it is defined in C: long int strtol(const char *str, char **endptr, int base); Functions used to define it in C: str : A pointer to the string that is to be converted to a long integer. endptr : A pointer used by strtol , which points to the first non-integer character signaled to stop conversion.
Is it safe to use printf in multithreaded programs?
These functions can safely be used in a multi-threaded program if and only if they are called while the invoking thread owns the ( FILE * ) object, as is the case after a successful call to the flockfile() or ftrylockfile() functions.
Is Vsnprintf thread safe?
It’s not thread safe, since the buffer where you sprintf is shared between all threads.
What does strtok_r return?
Return Value The first time the strtok_r() function is called, it returns a pointer to the first token in string. In later calls with the same token string, the strtok_r() function returns a pointer to the next token in the string. A NULL pointer is returned when there are no more tokens. All tokens are null-ended.
Do not use atoi () better use strtol ()?
The atoi() function is subsumed by strtol() but is retained because it is used extensively in existing code. If the number is not known to be in range, strtol() should be used because atoi() is not required to perform any error checking.
Is Scanf thread safe?
The standard C printf() and scanf() functions use stdio so they are thread-safe. The standard C printf() function is susceptible to changes in the locale settings if called in a multithreaded program.
Does printf use mutex?
In order not to mix the outputs from different threads, you need to make sure that only one thread uses printf at a time. To achieve this, the simplest solution is to use a mutex . At the beginning initialize the mutex : static pthread_mutex_t printf_mutex; …
Is Sscanf thread-safe?
The string-based functions, such as sprintf() and sscanf() , do not depend on the stdio library. These functions are thread-safe.
Is Va_start thread-safe?
As far as being serially-reentrant (ie., if foo() uses va_start is it safe for foo() to call bar() which also uses va_start ), the answer is that’s fine – as long as the va_list instance isn’t the same.
Is strtok_r safe?
The strtok() function need not be thread-safe. The strtok_r() function shall be equivalent to strtok(), except that strtok_r() shall be thread-safe and the argument state points to a user-provided pointer that allows strtok_r() to maintain state between calls which scan the same string.
What are strtol and wcstol?
The strtol, wcstol, _strtol_l, and _wcstol_l functions convert string to a long. They stop reading string at the first character not recognized as part of a number. It may be the terminating-null character, or the first alphanumeric character greater than or equal to base. wcstol and _wcstol_l are wide-character versions of strtol and _strtol_l.
What is the difference between strtol and ATOL?
strtol provides you with more flexibility, as it can actually tell you if the whole string was converted to an integer or not. atol, when unable to convert the string to a number (like in atol (“help”) ), returns 0, which is indistinguishable from atol (“0”): strtol will specify, using its endptr argument, where the conversion failed.
What is the base value of strtol () function?
base − This is the base, which must be between 2 and 36 inclusive, or be the special value 0. This function returns the converted integral number as a long int value, else zero value is returned. The following example shows the usage of strtol () function.