CODEWITHSUNDEEP
c++printf
Aeonos
Aeonos

Reputation: 387

Use one pointer for sprintf variadic argument

I am writing a function, that takes a variadic argument list and produces a formated string from those. The problem is, that i use sprintf to create the string and i need to explicity list all paramaters, while programming

sprintf(string, format, a0, a1, a2, ...);

On cppreference however the description of sprintf says, that ...

... (additional arguments) Depending on the format string, the function may expect a sequence of additional arguments, each containing a value to be used to replace a format specifier in the format string (or a pointer to a storage location, for n).

What i understand like, that i can store all the data to a pointer location and hand the pointer to sprintf.

int arr[X];
arr[0] = a0;
...
sprintf(string, format, &arr);

Trying that resulted in an unexpected behavior. Only numbers were written to the string.

Does it actually work that way and is there maybe a better solution?

My first attempt was to add each variadic argument separatly to the string, but that produced a lot of calls to sprintf, what i want to avoid.

Is it possible to pass the variadic argument list from one function to another?

Upvotes: 0

Views: 477

Answers (1)

Aeonos
Aeonos

Reputation: 387

Okay ... why did i not find this sooner... The solution for me was to use vsnprintf instead of sprintf. That way one can pass the va_list to a formated string function and it is secure.

How to pass variable number of arguments to printf/sprintf

Upvotes: 2

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