X-Git-Url: https://code.wpia.club/?a=blobdiff_plain;f=lib%2Fopenssl%2Fdoc%2Fcrypto%2FBIO_read.pod;fp=lib%2Fopenssl%2Fdoc%2Fcrypto%2FBIO_read.pod;h=b34528104ddf248813b68c666111f0316986aefc;hb=9ff1530871deeb0f7eaa35ca0db6630724045e4a;hp=0000000000000000000000000000000000000000;hpb=25b73076b01ae059da1a2e9a1677e00788ada620;p=cassiopeia.git diff --git a/lib/openssl/doc/crypto/BIO_read.pod b/lib/openssl/doc/crypto/BIO_read.pod new file mode 100644 index 0000000..b345281 --- /dev/null +++ b/lib/openssl/doc/crypto/BIO_read.pod @@ -0,0 +1,66 @@ +=pod + +=head1 NAME + +BIO_read, BIO_write, BIO_gets, BIO_puts - BIO I/O functions + +=head1 SYNOPSIS + + #include + + int BIO_read(BIO *b, void *buf, int len); + int BIO_gets(BIO *b,char *buf, int size); + int BIO_write(BIO *b, const void *buf, int len); + int BIO_puts(BIO *b,const char *buf); + +=head1 DESCRIPTION + +BIO_read() attempts to read B bytes from BIO B and places +the data in B. + +BIO_gets() performs the BIOs "gets" operation and places the data +in B. Usually this operation will attempt to read a line of data +from the BIO of maximum length B. There are exceptions to this +however, for example BIO_gets() on a digest BIO will calculate and +return the digest and other BIOs may not support BIO_gets() at all. + +BIO_write() attempts to write B bytes from B to BIO B. + +BIO_puts() attempts to write a null terminated string B to BIO B + +=head1 RETURN VALUES + +All these functions return either the amount of data successfully read or +written (if the return value is positive) or that no data was successfully +read or written if the result is 0 or -1. If the return value is -2 then +the operation is not implemented in the specific BIO type. + +=head1 NOTES + +A 0 or -1 return is not necessarily an indication of an error. In +particular when the source/sink is non-blocking or of a certain type +it may merely be an indication that no data is currently available and that +the application should retry the operation later. + +One technique sometimes used with blocking sockets is to use a system call +(such as select(), poll() or equivalent) to determine when data is available +and then call read() to read the data. The equivalent with BIOs (that is call +select() on the underlying I/O structure and then call BIO_read() to +read the data) should B be used because a single call to BIO_read() +can cause several reads (and writes in the case of SSL BIOs) on the underlying +I/O structure and may block as a result. Instead select() (or equivalent) +should be combined with non blocking I/O so successive reads will request +a retry instead of blocking. + +See L for details of how to +determine the cause of a retry and other I/O issues. + +If the BIO_gets() function is not supported by a BIO then it possible to +work around this by adding a buffering BIO L +to the chain. + +=head1 SEE ALSO + +L + +TBA