Add examples for output capture (fixes #691)

1 files changed, 51 insertions, 0 deletions

diff --git a/examples/qpdfjob-save-attachment.cc b/examples/qpdfjob-save-attachment.cc
new file mode 100644
index 00000000..2c08620a
--- /dev/null
+++ b/examples/qpdfjob-save-attachment.cc
@@ -0,0 +1,51 @@
+#include <qpdf/Pl_StdioFile.hh>
+#include <qpdf/QPDFJob.hh>
+#include <qpdf/QPDFLogger.hh>
+#include <qpdf/QUtil.hh>
+
+// This example demonstrates how we can redirect where saved output
+// goes by calling the default logger's setSave method before running
+// something with QPDFJob. See qpdfjob-c-save-attachment.c for an
+// implementation that uses the C API.
+
+int
+main(int argc, char* argv[])
+{
+    auto whoami = QUtil::getWhoami(argv[0]);
+
+    if (argc != 4) {
+        std::cerr << "Usage: " << whoami << " file attachment-key outfile"
+                  << std::endl;
+        exit(2);
+    }
+
+    char const* filename = argv[1];
+    char const* key = argv[2];
+    char const* outfilename = argv[3];
+    std::string attachment_arg = "--show-attachment=";
+    attachment_arg += key;
+
+    char const* j_argv[] = {
+        whoami,
+        filename,
+        attachment_arg.c_str(),
+        "--",
+        nullptr,
+    };
+
+    QUtil::FileCloser fc(QUtil::safe_fopen(outfilename, "wb"));
+    auto save = std::make_shared<Pl_StdioFile>("capture", fc.f);
+    QPDFLogger::defaultLogger()->setSave(save, false);
+
+    try {
+        QPDFJob j;
+        j.initializeFromArgv(j_argv);
+        j.run();
+    } catch (std::exception& e) {
+        std::cerr << whoami << ": " << e.what() << std::endl;
+        exit(2);
+    }
+
+    std::cout << whoami << ": wrote attachment to " << outfilename << std::endl;
+    return 0;
+}