docs/CURLOPT_WRITEFUNCTION: size is always 1 #2787
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For compatibility with `fwrite`, the `CURLOPT_WRITEFUNCTION` callback is passed two `size_t` parameters which, when multiplied, designate the number of bytes of data passed in. In practice, CURL always sets the first parameter (`size`) to 1. This practice is also enshrined in documentation and cannot be changed in future. The documentation states that the default callback is `fwrite`, which means `fwrite` must be a suitable function for this purpose. However, the documentation also states that the callback must return the number of *bytes* it successfully handled, whereas ISO C `fwrite` returns the number of items (each of size `size`) which it wrote. The only way these numbers can be equal is if `size` is 1. Since `size` is 1 and can never be changed in future anyway, document that fact explicitly and let users rely on it.
bagder
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xquery
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For compatibility with `fwrite`, the `CURLOPT_WRITEFUNCTION` callback is passed two `size_t` parameters which, when multiplied, designate the number of bytes of data passed in. In practice, CURL always sets the first parameter (`size`) to 1. This practice is also enshrined in documentation and cannot be changed in future. The documentation states that the default callback is `fwrite`, which means `fwrite` must be a suitable function for this purpose. However, the documentation also states that the callback must return the number of *bytes* it successfully handled, whereas ISO C `fwrite` returns the number of items (each of size `size`) which it wrote. The only way these numbers can be equal is if `size` is 1. Since `size` is 1 and can never be changed in future anyway, document that fact explicitly and let users rely on it. Closes curl#2787
falconindy
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Sep 10, 2018
For compatibility with `fwrite`, the `CURLOPT_WRITEFUNCTION` callback is passed two `size_t` parameters which, when multiplied, designate the number of bytes of data passed in. In practice, CURL always sets the first parameter (`size`) to 1. This practice is also enshrined in documentation and cannot be changed in future. The documentation states that the default callback is `fwrite`, which means `fwrite` must be a suitable function for this purpose. However, the documentation also states that the callback must return the number of *bytes* it successfully handled, whereas ISO C `fwrite` returns the number of items (each of size `size`) which it wrote. The only way these numbers can be equal is if `size` is 1. Since `size` is 1 and can never be changed in future anyway, document that fact explicitly and let users rely on it. Closes curl#2787
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For compatibility with
fwrite, theCURLOPT_WRITEFUNCTIONcallback ispassed two
size_tparameters which, when multiplied, designate thenumber of bytes of data passed in. In practice, CURL always sets the
first parameter (
size) to 1.This practice is also enshrined in documentation and cannot be changed
in future. The documentation states that the default callback is
fwrite, which meansfwritemust be a suitable function for thispurpose. However, the documentation also states that the callback must
return the number of bytes it successfully handled, whereas ISO C
fwritereturns the number of items (each of sizesize) which itwrote. The only way these numbers can be equal is if
sizeis 1.Since
sizeis 1 and can never be changed in future anyway, documentthat fact explicitly and let users rely on it.